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Silver Member Username: Thumpinwith8s2 RE8s, 300 watt Jense..., 133.3db@49hz!! Post Number: 287 Registered: Jun-07 | How do I go about finding out how many watts my amp is actually putting out? I am gonna get my DMM from work tonight and do it, but I need to know exactly how. and what is the formula to change it from what the DMM says to tell you what the wattage is? |
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Gold Member Username: InsearchofbassPost Number: 5545 Registered: Jun-04 | measure amperage with the dmm......amps times volts equals watts that will be true rms |
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Gold Member Username: InsearchofbassPost Number: 5546 Registered: Jun-04 | bump |
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Gold Member Username: InsearchofbassPost Number: 5547 Registered: Jun-04 | measure amperage with the dmm......amps times volts equals watts that will be true rms |
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Silver Member Username: Thumpinwith8s2 RE8s, 300 watt Jense..., 133.3db@49hz!! Post Number: 293 Registered: Jun-07 | ok, so do I measure the output with the subs hooked up and playing a test tone, or unhooked? and you said ampsXvolts=watts....ok, so I hook the dmm up to where the subs are wired up to the amp and that will give me the amps, right? then how do I get volts (i assume its 12volts..from the battery, right? |
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Gold Member Username: BernymacBME, BernyMac Edi... Post Number: 3046 Registered: Sep-04 | Either measure at 12.4 volts or so, car off, or measure it with car on and the voltage will be higher. Meaning more out of your amp with car on of course. |
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Silver Member Username: Thumpinwith8s2 RE8s, 300 watt Jense..., 133.3db@49hz!! Post Number: 294 Registered: Jun-07 | Berny, let me make sure I get this right. 1.measure the input into the amp to get volts 2. measure the output where the subs are wired to the amp to get amperage 3. Multiply them by each other to get the rms wattage that the amp is putting out. is that right? |
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Gold Member Username: Nd4spd18Southeast PA Post Number: 3086 Registered: Jul-06 | WTF, I'm surprised to here someone been here as long as Sean say something like this....... How to measure an amplifiers output power: http://www.bcae1.com/measpwr.htm You have to use resistors, you CAN NOT use speakers as the load, it will give you a false reading. You should also be using a bench power supply to power the amp, but if you have a really beefed up charing system in the car you can get by with that, IF the voltage doesn't drop. Also FYI this equipment needed to be able to do this is real expensive. |
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Silver Member Username: Thumpinwith8s2 RE8s,250 watt Jensen..., 133.3db@49hz!! Post Number: 298 Registered: Jun-07 | wowsers, guess I wont be able to do it. dam, i really would like to know what its putting out, whether its 250 or 300. |
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Silver Member Username: Thumpinwith8s2 RE8s,250 watt Jensen..., 133.3db@49hz!! Post Number: 299 Registered: Jun-07 | guess I'll have to go by these specs, which show it at 300rm at 4ohms bridged. http://www.savinglots.com/lotprod.asp?item=XA2250 |
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Silver Member Username: Thumpinwith8s2 RE8s on a 300 watt J..., 133.3db@49hz!! Post Number: 300 Registered: Jun-07 | did find out that its supposed to have 2 25 amp fuses, I think I have 20's will have to check |
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Gold Member Username: InsearchofbassPost Number: 5548 Registered: Jun-04 | MS I never said measure with the speakers bud |
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Gold Member Username: InsearchofbassPost Number: 5549 Registered: Jun-04 | as far as voltage drop it really shouldnt be an issue |
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Silver Member Username: JkidderSpring hill, Florida Usa Post Number: 940 Registered: Nov-05 | takes oscilloscope and other equipment to bench test an amp. u cant find out TRUE RMS with only a dmm. |
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Silver Member Username: Nnnnick_bWeddington, Nc Usa Post Number: 949 Registered: Jan-05 | The simple way to get a ball park estimate is to multiply the amps total fusing by the voltage output of your charging system (12-13 volts(engine off) 13.8-14.4(engine running)). Then multiply by the amps efficiency. A class AB(solid state) will be around 55-65% efficient. A class D(digital) will be around 75-80% efficient. Its not an exact science. EX. A kicker kx 600.1 has a stated rms output of 600watts. 60amps(fusing) x 13.8v(standard alternator output) x .8 = 662.4. The birthsheet stated the amp will do 715rms @ 14.4v. Close enough for government work. |